1. Field of the Invention
This invention is directed to devices which are used in the graphics industry, in general, and to high-accuracy, close-tolerance, lithographic techniques used in printed circuit board graphics, in particular.
2. Prior Art
In many industries, notably the electronic industry, there are developing more and more requirements for smaller and smaller devices. These smaller devices create greater density on the board or chip. As the density of devices, i.e., circuits, on the printed circuit board (for example) increases, the tolerance limits tend to decrease. Thus, techniques which were satisfactory for manufacturing processes ten years ago are no longer adequate for the manufacturing processes of today. This trend will, of course, continue. Nevertheless, in order to keep pace with this improving technology, the lithographic technology must also follow.
To this end, techniques have been developed using ion milling, ion etching, photosensitive materials and the like. Nevertheless, most of the known techniques require a suitable mask or image which is developed at a very large scale and reduced to form the image or mask for the actual production devices. The mask or image is then used with the actual device onto which the circuit, for example, is to be manufactured. These techniques include the well-known photosensitive techniques such as coating a circuit board with a polymer type material such as KPR or the like, exposing those materials to an appropriate light source through the imaging mask, and removing the undesirable material. This can be performed by producing a direct image, or a negative image, as the case may be. Of course, this operation is a function of the type of material which is used and the light source which is applied to sensitive portions of the masking material. When the undesired materials are removed, suitable plating, etching or similar type operations can be carried out. The etching can be a chemical etch, a laser etch or the like.
However, with the technology currently available, the technique of applying the mask or imaging material is extremely tedious and time consuming, as well as being subject to considerable human error problems. Despite the fact that many machines are now used which are vastly superior to earlier techniques, the shortcomings noted above still exist. Consequently, new and better registration devices are necessary.